It is well known that ground loops produced by various causes can contribute to electromagnetic compatibility (EMC) test failure of electrical circuits on integrated circuit boards used in electronic instruments. Further, with respect to EMC, when a ground-referenced signal is brought onto a particular board that is not well grounded, the board's circuit ground can become “hot” with the ground-reference signal, which in turn produces electromagnetic radiation.
Any resulting electromagnetic compatibility (EMC) test failures are undesirable. Electromagnetic compatibility (EMC) is generally understood to mean the ability of an electrical/electronic device to function properly in its normal operating context without interfering with the operation of other electrical/electronic devices.
Various solutions have been developed to help solve the above-noted EMC problems. In one of the solutions, integrated circuit boards are mounted to a conductive tray member which provides a conductive path to the equipment chassis through a plurality of electronically conductive standoff elements. The standoff elements are typically evenly distributed on the tray for short grounding paths. However, the tray/standoff approach is not particularly desirable when easy access to the circuit boards is required. Further, it is desirable that the circuit boards can slide out of the chassis conveniently without requiring use of a special tool, which is not the case with the tray/standoff structure.
In another solution, the printed circuit cards containing the electrical currents are electrically grounded to the instrument chassis through a back plane connector. In such an electrical grounding path arrangement, however, the circuit card is typically not directly connected to the equipment chassis and usually the ground path is relatively long. A direct, and short, electrical path from the circuit ground element to the chassis is important to satisfy the EMC requirements.